Recently, in color display devices used for displaying images on computers, televisions, and the like, a PDP display device using a PDP has draw attention as a color display device that can realize a large-screen and light weight display device.
A PDP includes a front panel and a rear panel sealed to each other with predetermined discharge space interposed therebetween. On the front panel and the rear panel, an electrode and a dielectric layer, or a barrier rib, a phosphor layer, and the like, are formed respectively by firing a structure containing an organic binder. Among the production processes of a PDP, in particular, in a sealing process for sealing the front panel and the rear panel, an organic binder, etc. contained in a glass frit used as a sealing material is thermally decomposed, so that impurity gas is dispersed inside the PDP. Main components of the impurity gas include water, carbon dioxide, hydrocarbon gas, and the like, and these impurity gases are adsorbed on a phosphor etc. in the PDP and may cause such problems as deterioration of discharge characteristics, degradation of luminance, and the like (disclosed in Japanese Patent Unexamined Publication No. 2003-281994 and FPD Technology Outlook (Electronic Journal, Oct. 25, 2000, pp 615-618)). Therefore, one of the important problems is to reduce impurity gas inside the PDP and to improve the reliability by stabilizing discharge characteristics and suppressing change over time.
As a method of reducing impurity gas inside of such a PDP, a method of providing a getter in an exhaust pipe so as to adsorb impurity gas when the inside of the PDP is exhausted is disclosed in Japanese Patent Unexamined Publication No. 11-329246, and a method of providing a getter inside a PDP so as to adsorb impurity gas is disclosed in Japanese Patent Unexamined Publication Nos. 2002-531918 and 2003-303555.
However, in the above-mentioned conventional method of providing a getter in an exhaust pipe, since discharge gas is injected through the exhaust pipe, the impurity gas exhausted from the inside of the PDP is adsorbed on the inner wall of the exhaust pipe and impurity gas enters the inside of the PDP again together with discharge gas when the discharge gas is supplied. Consequently, removal of impurity gas was not sufficient. Furthermore, in the method of providing a getter inside the PDP so as to adsorb impurity gas, since discharge space is partitioned by barrier ribs, the effect of the getter cannot be allowed to act on the entire region. As a result, a region in which impurity gas remains is generated, thus causing uneven display. Furthermore, a getter is heated during discharging, so that impurity gas may be released into the PDP again. Furthermore, in the method of providing a getter inside an exhaust pipe so as to remove impurity gas, impurity components gradually accumulate in the getter, thus gradually degrading the ability of removing impurity gas. Furthermore, since the main object of a conventional getter or adsorbent is to adsorb and remove water or carbon dioxide among impurity gas, such a getter or adsorbent has less effect in removing hydrocarbon gas.